1. Field of the Invention
The invention is related to the field of telecommunication networks and, in particular, to providing voice group sessions over telecommunication networks.
2. Statement of the Problem
There are a variety of ways to provide group communication services in a communication network. For a user that is connected to the internet through a properly-equipped PC, internet-based chat rooms and instant messaging (IM) are available. A chat room is a way of communicating by sending text-based messages to other people in the same chat room in real-time. When a chat room is established on the internet, multiple users may navigate to the chat room and join. The members of the chat room may then communicate with one another, typically through text. Instant messaging offers real-time communication between one or more parties simultaneously, typically through text. A user may establish an IM session with multiple people on a “contact list” as long as these people are online. The group involved in the IM session may then communicate in real time through text messages. Although these internet services are useful, each of them has shortcomings. Internet chat rooms are typically text-based, do not effectively support voice or multimedia content, and require an appropriate internet browser to access the chat rooms. IM is also typically text-based, does not scale well to large groups, and requires the appropriate software.
For a telecommunication user, one example of a group communication service is push-to-talk (PTT) service. PTT service (or Push to Talk over Cellular) resembles a walkie-talkie service over a cellular network. PTT calls are half duplex communications meaning that one person speaks, the others listen. Traditional cellular networks and devices utilize full-duplex communications, allowing customers to call other persons on a mobile or land-line network and be able to simultaneously talk and hear the other party. PTT service advantageously allows a user to initiate a group call to multiple parties simultaneously. For a group call, the user enters multiple parties into a talk group on his/her PTT device, and when the user keys the PTT button on the PTT device, the network establishes a half-duplex channel with each of the parties in the talk group. As the user speaks, the parties of the talk group are then able to listen to the user. After the user has finished speaking and is no longer keying the PTT button, other parties of the talk group may request the floor and speak to the group.
Although PTT services provide effective group sessions, there are problems associated with PTT. First, PTT requires a specific handset and service subscription that is limited to a few providers. Second, PTT service uses a sophisticated process for granting the floor for a PTT call to one of the users while the others listen, and then switching the floor to another user as requested.
As telecommunication networks evolve, more elaborate group communication services may be provided. One type of telecommunication network gaining popularity is an IP Multimedia Subsystem (IMS) network. As set forth in the 3rd Generation Partnership Project (3GPP), IMS provides a common core network having a network architecture that allows for various types of access networks. The access network between a communication device and the IMS network may be a cellular network (e.g., CDMA or GSM), a WLAN (e.g., WiFi or WiMAX), an Ethernet network, or another type of wireless or wireline access network. The IMS architecture is initially defined by the 3GPP to provide multimedia services to communication devices over an Internet Protocol (IP) network, as IP networks have become the most cost savings bearer network to transmit video, voice, and data. Service providers are accepting this architecture in next generation network evolution.
IMS users are thus able to receive multimedia services in a manner not previously offered. It is therefore desirable to provide effective chat sessions or other group communication sessions on an IMS network or other types of telecommunication networks that allow for exchange of voice, video, images, audio, or other multimedia data.